Knowing the Bank of Japan (BOJ) has a habit of disappointing, investors booked some profits on recent hefty gains. The Aussie eased 0.5 percent on the day to 94.22 yen , but remained close to Friday's peak of 95.02, a level not visited since 2008.
The kiwi slipped to 74.88 yen from 75.41 early, though within sight of Friday's 75.80 high, also the strongest since 2008. The Antipodeans are still up over 20 percent on the yen each in just two months.
Facing relentless political pressure, the BoJ is expected to at least top up its asset-buying and lending programme by another 10 trillion yen and double its inflation target to 2 percent at its Jan 21-22 meeting.
Dealers, however, are cautious as anything less than radical would see the yen rally.
"The challenge for the BoJ is to surprise the markets with something beyond 2 percent and 10 trillion, but history suggests they come up with underwhelming responses," said David Scutt, a trader at Arab Bank Australia.
"(Should it be the case), it will be 'sell the fact' and 'sell the fact hard' given the recent (one-way) positioning," he said, seeing the Aussie test a double-bottom near 92.5 yen.
On the longer-term, however, Scutt said the Aussie's target was well and truly above 100 yen.
A sustained recovery in the Japanese economy would certainly be welcome by Australia and New Zealand, for whom Japan is a major export market. It would also bolstering global growth, trade and commodity prices.
Chart resistance for the Aussie was seen at 95.45, the 76.4 percent of the 55.0/107.9 move and around 77.86 yen for the kiwi.
With all eyes on the BoJ, the Antipodeans marked time against the US dollar. The Aussie edged up to $1.0515, little changed from Friday's late local level, but within reach of a four-month peak around $1.0600 set earlier this month.
Initial support was found at around $1.0475/80, the 20-day moving average (MA), ahead of $1.0460, the 55-day MA. Resistance was seen at $1.0520.
The New Zealand dollar held steady at $0.8356, still digesting a hit following softer-than-expected inflation data on Friday. The reading backed the view that rates are likely to be held at record low 2.5 percent for some time.
"We have shifted our forecast for the first rate increase from December 2013 to March 2014," said ASB Bank senior economist Jane Turner.
Based on overnight indexed swaps, markets pricing now implies only four basis points (bps) of increase over the next 12 months from 8 bps a week ago, and no change at next week's rate review, the first for this year.
Technically, the kiwi remained well supported at $0.8325 with resistance around $0.8380. It remained within reach of a 16-month high of $0.8477 struck in December.
The Aussie and kiwi dollars shot up to multi-month highs against a floundering pound which plumbed to A$1.5056 , its weakest since August and to NZ$1.8921 , its lowest in nearly a year.
Sterling has come under pressure across the board after weaker-than-expected retail sales data at home on Friday combined with fears of a return to recession with GDP figures due out on Friday.
It has skidded more than 3 percent this year against each of the Antipodean currencies and charts suggest further downside. The 5, 10- and 20-day MA point south with support seen at A$1.5000, the lower edge of the Ballinger band, ahead of A$1.4850.
Against the kiwi, pound support was seen at NZ$1.8800, ahead of NZ$1.8620, the 2012 trough.
New Zealand government bonds were firmer, with yields staying a tick lower across the curve.
Australian bond futures edged up with the three-year contract up 0.02 points to 97.220, and the 10-year contract 0.035 points higher at 96.650.